test(swap): 添加部分平仓利息计算测试用例

- 添加算尾部分平仓当日新计利息包含已平仓部分的测试
- 添加不算尾部分平仓当日新计利息只包含剩余持仓部分的测试
- 验证部分平仓待实现收益计算的正确性

UnitTestProject/Modules/SwapModule/DealInterestsScenarioTest.cs

@@ -807,6 +807,50 @@ namespace YLErp.Modules.SwapModule
                 "预付金部分平仓待实现收益应为历史待实现+平仓后当日新增-平仓实现");
         }
 
+        [TestMethod]
+        public void DI_MANUAL_PARTIAL_CLOSE_CalcLastIncludesClosedPrincipalDailyInterest()
+        {
+            var service = new StubEodPositionService();
+            var td = CreateTrade();
+            td.trade_extend.ExtendJson = JsonConvert.SerializeObject(new TradeExtendJson
+            {
+                AnnualDays = AnnualDays,
+                InterestCalcMode = "11",
+                SettlementRules = 0
+            });
+            var position = CreateInterestPosition();
+            var previousEod = CreatePreEod(StartDate.AddDays(2), 100m);
+            previousEod.TdInterestPrincipal = Principal;
+            var closeFlow = CreateSwapFlowEvent(StartDate.AddDays(3), 50m);
+            closeFlow.EventType = (int)SwapFlowEventTypeEnum.平仓;
+
+            var result = service.ExecuteSaveAutoEodWithCloseInterestPosition(
+                previousEod, position, td, StartDate.AddDays(3), null,
+                500m, 0m, new List<swap_flow_event> { closeFlow }, 500m, false);
+
+            AssertDecimal(Principal * FixedRate / AnnualDays, result.TdInterestIncome,
+                "算尾部分平仓的当日新计利息应包含已平仓部分");
+        }
+
+        [TestMethod]
+        public void DI_MANUAL_PARTIAL_CLOSE_NoCalcLastUsesRemainingPrincipalDailyInterest()
+        {
+            var service = new StubEodPositionService();
+            var td = CreateTrade();
+            var position = CreateInterestPosition();
+            var previousEod = CreatePreEod(StartDate.AddDays(2), 100m);
+            previousEod.TdInterestPrincipal = Principal;
+            var closeFlow = CreateSwapFlowEvent(StartDate.AddDays(3), 50m);
+            closeFlow.EventType = (int)SwapFlowEventTypeEnum.平仓;
+
+            var result = service.ExecuteSaveAutoEodWithCloseInterestPosition(
+                previousEod, position, td, StartDate.AddDays(3), null,
+                500m, 0m, new List<swap_flow_event> { closeFlow }, 500m, false);
+
+            AssertDecimal(500m * FixedRate / AnnualDays, result.TdInterestIncome,
+                "不算尾部分平仓的当日新计利息只应包含剩余持仓部分");
+        }
+
         [TestMethod]
         public void DI_AUTO_SETTLEMENT_005_AutoSettlementKeepsRemainingPrincipal()
         {